Aircraft wheel brake device

Abstract

A device (1) for braking a wheel (2) of an aircraft, wherein the wheel hub (5a, 5b) is mounted for rotation about an axle (6), and comprises a stack of wheel discs (11) screwed onto a torque tube (12) attached to the axle and internally provided with a heat shield (20) extending opposite the outer surface (5.1) of the wheel hub facing the stack of wheel discs to protect the wheel hub from the heat radiation generated by the stack of wheel discs. The heat shield comprises a tubular body (21) coaxial with the torque tube and a plurality of retaining tabs (22) elastically deformable and fixed to the tubular body, each retaining tab and the inner surface (12.1) of the torque tube comprising an additional raised portion intended to engage with each other so as to secure the heat shield axially inside the torque tube. A wheel, landing gear and aircraft are provided with such a braking device.

Description

Technical Field

[0001] The present invention relates to the field of braking, and more particularly to controlling heat transfer during braking. Background Art

[0002] Aircraft landing gear typically includes a strut having a first end connected to the aircraft structure and a second end provided with a shaft or axle, on which a wheel is rotatably mounted. The wheel includes a rim connected to a hub via a web. The hub receives the strut's shaft via bearings, and the hub and rim together define a space within which a stack of brake discs is disposed. The disc stack alternately includes stator discs rotatably secured to a torque tube coaxial with the wheel hub, and rotor discs rotatably secured to the wheel rim. An actuator, such as a hydraulic jack, is arranged to apply pressure to the disc stack via a hydraulic ring, thereby braking the wheel.

[0003] The heat release from the friction of the discs can be significant (particularly during landing of the aircraft, when the energy to be dissipated is greatest due to its mass and high speed) and can lead to overheating of the brake and its environment. This problem is addressed in particular in document EP-A-3702275.

[0004] Especially for safety reasons, the maximum temperature of the wheel hub is about 200 ° C to ensure its mechanical strength, but also to avoid overheating of the bearing and its sealing system, which may lead to premature bearing failure.

[0005] It is therefore known to provide a thermal insulation between the wheel hub and the torque tube in order to protect the wheel hub from the heat radiation generated by the wheel disc stack.

[0006] Certain thermal shields extend from the web of the wheel to the inner shoulder of the torque tube, forming a tube base to which the thermal shields are screwed to hold them in place inside the torque tube.

[0007] However, if such thermal insulators prove effective, they require the torque tube to be provided with a base to enable their attachment thereto, which increases the mass of the torque tube and also complicates its shape, thereby complicating its manufacture, installation and maintenance.

[0008] Other thermal insulators have one end sandwiched between the hydraulic ring and the bottom of the torque tube, and the other end screwed to the free edge of the torque tube via a connecting piece. These thermal insulators extend the entire length of the torque tube, which tends to increase heating of the torque tube. Furthermore, the presence of the connecting piece connecting the thermal insulator to the free edge of the torque tube has the effect of increasing the cost and mass of the assembly.

[0009] Furthermore, such thermal insulation requires the use of tools to screw the thermal insulation to the torque tube, which results in preparation work and significant installation time. Summary of the Invention

[0010] The present invention therefore aims to propose a thermal insulation element which makes it possible to at least partially overcome the above-mentioned problems.

[0011] To achieve this objective, the present invention provides a braking device for an aircraft wheel, wherein the wheel hub is rotatably mounted on a wheel axle. The device comprises a wheel disc stack screwed (or threaded) onto a torque tube. The torque tube is attached to the wheel axle and internally equipped with a thermal insulator. The thermal insulator extends opposite an outer surface of the wheel hub facing the wheel disc stack to protect the wheel hub from heat radiation generated by the wheel disc stack.

[0012] According to the present invention, the thermal insulation member includes a tubular body coaxial with the torque tube and a plurality of retaining tabs, which are elastically deformable and fixed to the tubular body, and each retaining tab and the inner surface of the torque tube include an additional raised portion that engages with each other, thereby axially fixing the thermal insulation member inside the torque tube.

[0013] The thermal insulation is thus elastically retained in the torque tube.The retaining tabs thus enable the thermal insulation to be mounted inside the torque tube without tools and reduce its mounting time while limiting the cost and mass of the assembly.

[0014] According to a particular feature, the tubular body extends from the web of the wheel and the free edge of the hub.

[0015] The thermal insulation therefore only partially covers the inner surface of the torque tube, which tends to limit heating of said torque tube during braking.

[0016] Specifically, the tubular body includes a spherical cap-shaped marking facing the inner surface of the torque tube to form a punctual contact with the inner surface of the tube.

[0017] These markings make it possible to ensure the mechanical strength of the thermal insulation while limiting the heat conduction between the body and the torque tube.

[0018] According to a particular feature, the retaining tabs are evenly distributed around the central axis of the tubular body.

[0019] Specifically, the inner surface of the torque tube includes a radially protruding step, each retaining tab includes a fastening raised portion of the step, and preferably, at least one retaining tab includes a transverse groove arranged to engage with both the front and rear surfaces of the step.

[0020] Advantageously, the depth of the groove is less than the height of the step so that the retaining tab is removed from the inner surface of the torque tube, thereby limiting heat conduction between the thermal barrier and the torque tube.

[0021] In particular, at least one retaining tab comprises an inclined end portion forming a ramp on which the step bears and slides by causing elastic deformation of the retaining tab until passing the step during the introduction of the thermal insulation into the torque tube.

[0022] Specifically, the retaining tab defines a diameter that is smaller than the inner diameter of the torque tube and larger than the outer diameter of the tubular body.

[0023] In particular, the at least one retaining tab is formed integrally with the main body.

[0024] The invention also relates to an aircraft wheel equipped with such a braking device.

[0025] The invention also relates to an aircraft landing gear comprising at least one such wheel.

[0026] The invention also relates to an aircraft equipped with such an undercarriage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be best understood from the following description, which is purely illustrative and non-limiting and must be read in conjunction with the accompanying drawings, which include:

[0028] Figure 1 is an axial cross-sectional view of a wheel equipped with a braking device according to a specific embodiment of the present invention;

[0029] Figure 2 yes Figure 1 a perspective view of the torque tube and thermal insulation of the illustrated brake assembly;

[0030] Figure 3 yes Figure 2 A perspective view of the thermal barrier shown in place inside the torque tube;

[0031] Figure 4 yes Figure 2 A detailed view of one of the retaining tabs of the thermal insulation shown in ;

[0032] Figure 5 Schematically shows Figure 4 The resilient interlocking of the retaining tabs on the torque tube as shown in ; and

[0033] Figure 6 yes Figure 4 Detailed view of one variation of the retaining tab shown in . DETAILED DESCRIPTION

[0034] In this example, the invention is described as applied to an aircraft comprising at least one main landing gear having a strut, a first end of which is articulated to the structure of the aircraft and a second end provided with an axle on which at least one wheel is rotatably mounted.

[0035] refer to Figure 1 The present invention relates to a braking device, generally indicated at 1, which is equipped on a wheel 2 of the main landing gear of an aircraft.

[0036] The wheel 2 comprises two wheel halves 2a, 2b, each comprising an annular rim 3a, 3b connected by webs 4a, 4b to half-hubs 5a, 5b pivotally received on an axle or spindle 6 by means of bearings 7, 8. The wheel half 2a comprises a groove formed in the edge of the rim 3a and has a sealing gasket 9 arranged therein so that the sealing gasket 9 is elastically compressed between the wheel halves 2a, 2b once the wheel halves 2a, 2b are assembled.

[0037] The wheel halves 2a, 2b move towards each other in a direction parallel to the axis of rotation X of the wheel 2 and include surface areas to ensure that the two wheel halves 2a, 2b are properly positioned relative to each other. The wheel halves 2a, 2b are held in place by bolts 10 extending into bearing apertures in the webs 4a, 4b facing each other.

[0038] In a manner known per se, the wheel halves 2a, 2b are assembled together by tightening the bolts 10 after the tire (not shown) has been mounted on the rims 3a, 3b. In this position, the sealing gasket 9 is elastically compressed between the wheel halves 2a, 2b, thus preventing the gas contained in the volume delimited by the tire and the wheel halves 2a, 2b from escaping outside the wheel 2.

[0039] The brake device 1 comprises a brake disc 11 comprising a stator disc 11a and a rotor disc 11b, which are stacked alternately against each other on a torque tube 12, which is attached to a collar 13 of the axle. The torque tube 12 and the disc stack 11 extend in an annular space inside the wheel half 2a, which is defined by the inner surface of the rim 3a, the web 4a and the outer surface of the half hub 5a, which extends opposite the inner surface of the rim 3a.

[0040] The stator disk 11a is rotationally fixed relative to the axle 6, and the rotor disk 11b comprises axial peripheral recesses, each receiving a segment of a rod (not shown in the figures) attached to the inner surface of the rim 3a. The rod extends about an axis parallel to the axis of rotation X of the wheel 2 and ensures that the rotor disk 11b is coupled in rotation with the rim 3a about said axis X.

[0041] Braking device 1 further comprises a hydraulic ring 15, which is attached to the end of torque tube 12 by means of screws 16. Ring 15 comprises a plurality of cavities 17, which in this example are evenly distributed around axis of rotation X of wheel 2. Each cavity 17 receives an actuator 18 which selectively applies a braking force to a first stator disc 11 a of disc stack 11 via a pressurized hydraulic fluid circulating inside ring 15. The annular distribution of actuators 18 makes it possible to distribute the braking force evenly over the entire surface of first stator disc 11 a.

[0042] The braking device 1 is equipped with a tubular thermal insulation 20, which extends coaxially with the torque tube 12 between the cylindrical inner surface 12.1 of the torque tube 12 and the outer surface 5.1 of the half-hub 5a facing the wheel disc stack 11, so as to protect the half-hub 5a from heat radiation caused by the friction of the wheel discs 11 during braking of the wheel 2.

[0043] like Figure 2 and Figure 3 As shown, the thermal insulator 20 includes a cylindrical body 21 having an outer diameter slightly smaller than the diameter of the inner surface 12.1 of the torque tube 12. The body 21 extends from the web to the free edge 5.2 of the half-hub 5a, so that the thermal insulator 20 only partially covers the inner surface 12.1 of the torque tube 12. The body 21 includes a plurality of printed marks 21.1, which are symmetrically distributed about the central axis of the body 21 in this example. The printed marks 21.1 are spherical cap-shaped, have a convexity directed toward the inner surface 12.1 of the torque tube 12, and form a punctual contact with the inner surface 12.1 of the torque tube 12 to ensure the mechanical strength of the thermal insulator 20 while limiting heat conduction between the body 21 and the torque tube 12.

[0044] The thermal barrier 20 further comprises three elastically deformable retaining tabs 22 which bear against annular steps 19 protruding radially from the inner surface 12 . 1 of the torque tube 12 to elastically retain the thermal barrier 20 in position inside the torque tube 12 .

[0045] The step 19 comprises a front face 19.1 and a rear face 19.2, both of which are truncated and joined together by their large base.

[0046] The retaining tabs 22 project mainly axially from the edge of the body 21 , extending towards the hydraulic ring 15 , and in this example are evenly distributed around this edge.

[0047] according to Figure 4The retaining tab 22 is arranged to resiliently retract upon contact with the step 19 during the introduction of the thermal insulation 20 into the torque tube 12 and to resist axial movement of the body 21 once the thermal insulation 20 is in place in said torque tube 12. To this end, the retaining tab 22 has a mainly rectilinear central portion 22.1 provided in its middle with a marking forming a transverse groove 23, the transverse groove being arranged with flanks that engage simultaneously and respectively with the front face 19.1 and the rear face 19.2 of the step 19; and an inclined end portion 22.2 forming a ramp on which the front face 19.1 of the step 19 bears and slides during the introduction of the thermal insulation 20 into the torque tube 12 by causing elastic deformation of the retaining tab 22 until it passes the step 19. The angle formed by the side wings of the groove 23 and the surfaces 19.1, 19.2 of the step 19 with the central axis is greater than the angle formed between the end portion 22.2 and the central axis, so that when an axial force is applied to the thermal insulation element 20, the side wings of the groove 23 and / or the surfaces 19.1, 19.2 of the step 19 cannot act as a slope to promote deformation of the retaining tab 22 toward the central axis.

[0048] The retaining tab 22 also has a connecting portion 22 . 3 which connects the central portion 22 . 1 to the edge of the main body 21 .

[0049] It should be noted that the depth of the groove 23 is less than the height of the step 19, so that when the thermal insulation 20 is in place in the torque tube, the side wings of the groove press against the front and rear faces of the step 19 respectively, and when the retaining tab 22 is in a stationary state, the outer diameter of the central portion 22.1 of the retaining tab 22 is slightly larger than the outer diameter of the main body 21 and slightly smaller than the diameter of the inner surface 12.1 of the torque tube 12, so that the retaining tab contacts the torque tube 12 only at the groove 23, which makes it possible to limit any degradation of the torque tube 12 during its operation.

[0050] Now it will be based on Figure 5 The installation of the thermal insulation member 20 on the torque tube 12 will be described in detail.

[0051] The thermal insulator 20 is first introduced into the interior of the torque tube 12 coaxial therewith until the end portion 22.2 of the retaining tab 22 contacts the front face 19.1 of the step 19 of the torque tube 12. As the thermal insulator 20 continues to be inserted into the torque tube 12, the step 19 exerts a radial force on the end portion 22.2, which tends to deform the retaining tab 22 so that the retaining tab 22 is directed toward the central axis until the step 19 engages in the groove 23, thereby axially securing the body 21 inside the torque tube 12.

[0052] If the inclination of the end portion 22.2 facilitates the installation of the thermal insulation element 20, it should be noted that it also facilitates its removal. In fact, the operator can easily deform the retaining tab by applying an axial force under the end portion 22.2, thereby releasing the step 19 from the groove 23 while applying a withdrawal force on the thermal insulation element 20.

[0053] Figure 6 Shown is a retaining tab 22' which is Figure 4 A variation of the retaining tab 22 is shown. The retaining tab 22' differs from the retaining tab 22 in that it comprises a reinforcement 24 formed by a printed mark extending between the edge of the body 21 and the groove 23, in order to increase its rigidity.

[0054] Of course, the invention is not limited to the embodiments described but covers any variant coming within the ambit of the invention as defined by the claims.

[0055] The thermal insulation member 20 may be made of a thermally insulating material, such as steel, stainless steel, titanium, or the like.

[0056] The shape, number, distribution and size of the retaining tabs 22, 22' may vary from that shown.

[0057] Instead of groove 23, retaining tabs 22, 22' may be provided with radially outwardly projecting steps to be fastened behind step 19. It can be arranged that the steps of some tabs bear against the front face of step 19 and others against the rear face of step 19.

[0058] The shape and size of the step 19 may be different from that shown. The angles formed by the face portions 19.1, 19.2 of the step 19 with the central axis of the body 21 may in particular be different from and / or unequal to the angles of the step 19. Figure 6 Specifically, the angle formed between the front portion 19.1 and the central axis may include:

[0059] between 4 and 45 degrees, so as to form a so-called “smooth” slope, making it more or less easy to mount the thermal insulation 20 on the torque tube 12 ; or

[0060] between 45 and 90 degrees, so as to form a so-called “strong” slope, making the installation of the thermal insulation 20 on the torque tube 12 more or less difficult.

[0061] Similarly, the angle formed between the front face 19.2 and the central axis may comprise:

[0062] - between 5 and 45 degrees, making it more or less easy to remove the thermal insulation element 20; or

[0063] Between 45 and 90 degrees, the removal of the thermal insulation element 20 is made more or less difficult.

[0064] Instead, a recess may be formed on the inner surface of the torque tube 12 , and the retaining tabs 22 , 22 ′ may be provided with radially outwardly projecting steps to penetrate into the recess and secure the thermal barrier 20 in place in the torque tube 12 .

[0065] The retaining tabs may be cut in the tubular body and extracted from the edge of the tubular body.

[0066] Although the retaining tabs 22 , 22 ′ are formed integrally with the main body 21 in this example, they may also be applied to the main body 21 .

[0067] The number, shape and placement of the reinforcement members 24 may vary. Figure 6 Different as shown.

Claims

1. A braking device (1) for braking an aircraft wheel (2), the hub (5a, 5b) of the aircraft wheel being rotatably mounted on an axle (6), the braking device comprising a wheel disc stack (11) screwed onto a torque tube (12), the torque tube being attached to the axle and internally provided with a heat shield (20), the heat shield extending relative to an outer surface (5.1) of the hub facing the wheel disc stack to protect the hub from heat radiation generated by the wheel disc stack, the heat shield comprising a tubular body (21) coaxial with the torque tube and a plurality of retaining tabs (22), the plurality of retaining tabs being elastically deformable and fixed to the tubular body, each retaining tab and the inner surface (12.1) of the torque tube comprising an additional raised portion engaging with each other, thereby axially securing the heat shield inside the torque tube.

2. The braking device (1) according to claim 1, characterized in that The tubular body (21) extends from the web (4a, 4b) of the wheel and the free edge (5.2) of the hub (5a, 5b).

3. The braking device (1) according to claim 2, characterized in that The tubular body (21) comprises a circular cap-shaped marking (21.1), which faces the inner surface (12.1) of the torque tube (12) to form a punctual contact with the inner surface of the tube.

4. The braking device (1) according to claim 1 or 2, characterized in that The retaining tabs (22) are evenly distributed around the central axis of the tubular body (21).

5. The braking device (1) according to claim 1 or 2, characterized in that The inner surface (12.1) of the torque tube comprises a radially protruding step (19), and each of the tabs (22) is used to hold a fastened raised portion of the step.

6. The braking device (1) according to claim 5, characterized in that At least one of the retaining tabs (22) comprises a transverse groove (23) arranged to engage simultaneously with the front face (19.1) and the rear face (19.2) of the step (19).

7. The braking device (1) according to claim 6, characterized in that The depth of the transverse groove (23) is less than the height of the step, so that the retaining tab (22) can be removed from the inner surface of the torque tube.

8. The braking device (1) according to claim 5, characterized in that At least one of the retaining tabs (22) comprises an inclined end portion (22.2) forming a ramp, on which the step (19) bears and slides by causing elastic deformation of the retaining tab until the step is passed during the introduction of the thermal insulation (20) into the torque tube (12).

9. The braking device (1) according to claim 5, characterized in that The retaining tab (22) defines a diameter that is smaller than the inner diameter of the torque tube (12) and larger than the outer diameter of the tubular body (21).

10. The braking device (1) according to claim 1 or 2, characterized in that At least one of the retaining tabs (22) is integrally formed with the body (21).

11. An aircraft wheel (2) equipped with a braking device (1) according to any one of claims 1 to 10.

12. Aircraft landing gear comprising at least one aircraft wheel (2) according to claim 11.

13. An aircraft comprising at least one aircraft landing gear according to claim 12.

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